Organic light emitting devices (OLEDs) can suffer reduced output or premature failure when exposed to water vapor or oxygen. Metals and glasses have been used to encapsulate and prolong the life of OLED devices, but metals typically lack transparency and glass lacks flexibility. Intensive efforts are underway to find alternative encapsulation materials for OLEDs and other electronic devices. A flexible polymeric barrier film that exhibited low permeability to water vapor and oxygen would be especially useful, but despite intense industrial effort only limited success has been attained thus far. References relating to flexible barrier films include U.S. Pat. Nos. 5,440,446 (Shaw et al.), 5,530,581 (Cogan), 5,681,666 (Treger et al.), 5,686,360 (Harvey, III et al.), 5,736,207 (Walther et al.), 6,004,660 (Topolski et al.), 6,083,628 (Yializis), 6,146,225 (Sheats et al.), 6,214,422 (Yializis), 6,268,695 (Affinito), 6,358,570 (Affinito), 6,413,645 (Graff et al.), 6,492,026 (Graff et al.) and 6,497,598 (Affinito), 6,497,598 B2 (Affinito), 6,570,325 B2 (Graff et al.), 6,623,861 B2 (Martin et al.) and US 2002/0176993 A1 (Graff et al.); European Patent No. EP 0 777 280 B1 (Motorola, Inc.) and PCT Published Application No. WO 97/16053 (Robert Bosch GmbH). The Walther et al. patent describes a barrier assembly for plastic containers, with the lowest reported oxygen transmission rate being 0.375 cc/m2/day/bar.